Radio communication terminal, radio communication terminal housing case, radio communication terminal sheet and radio communication terminal display device

ABSTRACT

A radio communication terminal of one example of the present invention is a radio communication terminal provided with an electronic device shielded to prevent electromagnetic interference, in a housing, and comprises an integrated circuit, a first resonant circuit for making non-contact communication with an external device, and a second resonant circuit resonating with the first resonant circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2004-346483, filed Nov. 30, 2004,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radio communication terminal having anon-contact communication function of making radio communication usingan induced magnetic field between a non-contact IC card reader/writerdevice (hereinafter referred to as reader/writer) by being placed in theinductive magnetic field radiated from an antenna of the reader/writer.The present invention relates to, for example, a portable phone having anon-contact IC card function used by holding it up to the antenna of thereader/writer at an automatic ticket gate installed at a ticket gate ina railroad station.

The present invention relates to a radio communication terminal housingcase for housing such a radio communication terminal. The presentinvention relates to a radio communication terminal sheet capable ofbeing mounted on the radio communication terminal. The present inventionrelates to a radio communication terminal display device capable ofbeing mounted on the radio communication terminal.

2. Description of the Related Art

As a conventional non-contact IC card (hereinafter referred to as ICcard), one which is used at the automatic ticket gate installed at theticket gate in the railroad station is known for example. This IC cardhas an integrated circuit (IC) for processing a plurality ofcalculations and controls and has a resonant circuit for makingnon-contact communication with an external device, and the resonantcircuit is sometimes composed of a loop coil, a capacitor and a resinmaterial covering the IC. Such an IC card sometimes has the resonantcircuit having no capacitor.

The loop coil, the capacitor and a capacitor component parasitic on orset to the connecting part of the IC compose the resonant circuitresonating with the induced magnetic field radiated from the antenna ofthe reader/writer on the automatic ticket gate side. This conventionalIC card utilizes a voltage induced by the resonant circuit to generateoperation power for the IC from a power supply circuit of a rectifyingcircuit, etc., of the IC and performs communication, control and datawriting and reading to and from a memory.

In recent years, a variety of radio communication terminals such as aportable phone with a function owned by this type of IC cardincorporated therein have been come into existence. This radiocommunication terminal is very small in size. Therefore, it cannot mounta loop coil with a size larger than the loop area to obtain theoperation power necessary for the IC card. Accordingly, most of the ICcards are structured in which the operation power for an IC (hereinafterreferred to as non-contact IC) incorporated in the communicationterminal to have a function equivalent to that of the IC card and issupplied form a battery of the communication terminal and a small sizeof a loop coil is employed for use in communication. Since thecommunication terminal has electronic components and the battery toachieve a variety of terminal functions thereinside other than acommunication function (phone function), it has a metal member (radiowave shielding object) to prevent the influence (noise, etc.) of thecommunication function onto the incorporated electronic components.Then, the communication terminal is miniaturized as mentioned above, sothat there is the metal member close to or back face of the mounted loopcoil for the housing of inner components in the communication terminal.

Therefore, the magnetic field radiated from the loop coil generates aneddy current on the surface of the metal member to suppress the magneticfield, so that the density of the magnetic field becomes weak as aresult. To solve such a problem, a technique to make the loop coilmovable and to form a gap between the loop coil and the metal member isdisclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-330898.

However, other problems such that a trouble to be required to purposelymove the loop coil at communication, a movable section is damaged, thecost of the communication terminal equipment is increased on ground ofthe mounting of the movable section, etc.

There is a method for improving the magnetic field intensity on a loopcoil front face by inserting a ferrite material, etc., between the loopcoil and a metal plate and securing high magnetic permeability whilesuppressing a magnetic loss so as to reduce the influence of the eddycurrent on the back face of the loop coil. Although the magnetic fieldintensity on the front face of the loop coil can be improved by thismethod, it is impossible to generate a similar magnetic field at therear of the metal plate disposed on the back face of the loop coil.

Meanwhile, the communication though the IC card is one to demodulatevariations of the introduced magnetic field radiated from thereader/writer to receive data and one in a load switching system toreply the data to the reader/writer by switching the loop coil receivingthe induced magnetic field radiated from the reader/writer to vary aspace impedance with the induced magnetic field related thereto and byutilizing a part of energy of the induced magnetic field.

Consequently, in the case that the front face of the loop coil mountedon the radio communication terminal is held up so as to face theantenna, the loop coil can generate an extremely strong induced powercompared to the case that the back face of the loop coil is held up soas to face the antenna. As a result, this large difference in inducedpower comes out as a difference in a communication distance betweenfront face holding up and back face holding up.

Therefore, the portable phone prints a mark on a housing side with theloop coil mounted thereon and displays a face to be held up toward thereader/writer. However, in the case that the portable phone is used atthe automatic ticket gate installed at the ticket gate in the railroadstation, wrong faces are frequently held up because passengers are inhurry, and such problems of occurrence of passage interference such asfrequent closing of the ticket gate and the problem of incompleteprocessing such as entrance with a portable phone which is in a state ofprocessing incompletion occur.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a radio communicationterminal, a radio communication terminal housing case, a radiocommunication terminal sheet and a radio communication terminal displaydevice, capable of stabilizing communication with a reader/writer.

A radio communication terminal of one example of the present inventionis a radio communication terminal provided with an electronic deviceshielded to prevent electromagnetic interference, in a housing,comprising: an integrated circuit; a first resonant circuit connected tothe integrated circuit to make non-contact communication with anexternal device; and a second resonant circuit resonating with the firstresonant circuit.

A radio communication terminal housing case of one example of thepresent invention is a radio communication terminal housing case tohouse a radio communication terminal provided with a first resonantcircuit connected to an integrated circuit to make non-contactcommunication with an external device, comprising: a second resonantcircuit resonating with the first resonant circuit.

A radio communication terminal sheet of one example of the presentinvention is a radio communication terminal sheet enabled to attach to aradio communication terminal provided with a first resonant circuitconnected to an integrated circuit to make non-contact communicationwith an external device, comprising: a second resonant circuitresonating with the first resonant circuit.

A radio communication terminal display device of one example of thepresent invention is a radio communication terminal display deviceenabled to attach a radio communication terminal provided with a firstresonant circuit connected to an integrated circuit to make non-contactcommunication with an external device, comprising: a second resonantcircuit resonating with the first resonant circuit; and light emittingmeans emitting light by a current induced by the second resonantcircuit.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is a view showing an example of a schematic configuration of aradio communication terminal (for example, portable phone) regarding anembodiment of the present invention and a radio reader/writer of acommunication partner of the radio communication terminal;

FIGS. 2A and 2B are views showing a configuration example 1 of the radiocommunication terminal;

FIGS. 3A and 3B are views showing a configuration example 2 of the radiocommunication terminal;

FIGS. 4A and 4B are views showing a configuration example 3 of the radiocommunication terminal;

FIG. 5 is a view showing a configuration example 4 of the radiocommunication terminal;

FIG. 6 is a view showing a configuration example 5 of the radiocommunication terminal;

FIG. 7 is a view showing a configuration example 6 of the radiocommunication terminal;

FIG. 8 is a view showing a configuration example of a second resonantcircuit applicable to the configuration examples 4, 5 and 6 of the radiocommunication terminal;

FIG. 9 is a view showing an example of a radio communication terminalhousing case for housing the radio communication terminal;

FIG. 10 is a view showing an example of a radio communication terminalsheet capable of being mounted (stuck) on the radio communicationterminal; and

FIG. 11 is a view showing an example of a radio communication terminaldisplay device capable of being mounted (stuck) on the radiocommunication terminal.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described byreferring the drawings.

FIG. 1 is the view showing the example of the schematic configuration ofthe radio communication terminal (for example, portable phone) regardingthe embodiment of the present invention and the radio reader/writer ofthe communication partner of the radio communication terminal.

A radio communication terminal 100 has a communication function (phoneand data communication), a plurality of inner devices/circuits (maincontrol unit 131, etc.) achieving a variety of terminal functions and ashield for preventing electromagnetic interference of the innerdevices/circuits by means of this communication function and also has afirst resonant circuit 110, a second resonant circuit 120, an IC 132(referring to as non-contact IC), a connecting line 133 and the like.The first resonant circuit 110 is composed of a first loop coil 111 anda first capacitor 112 for communication. The second resonant circuit 120is composed of a second loop coil 121 and a second capacitor 122 forcommunication and is not electrically connected to the first resonantcircuit.

A non-contact IC 132 is supplied operation power from a battery (battery145 shown in FIG. 2B) and connected to the main control unit 131 throughthe connecting line 133. Furthermore, this non-contact IC 132 and thefirst loop coil 111 are connected each other.

In this embodiment, the shapes of the first loop coil 111 and the secondloop coil 121 are formed in rectangular shape and wound n times,respectively. The first capacitor 112 is used for resonance adjustmentof the first resonant circuit 110. In similarity, the second capacitor122 is used for resonance adjustment of the second resonant circuit 120.The first and the second capacitors 112 and 122 are sometimes notnecessary to be provided according to the resonance adjustment. Forexample, a substitute article for the first capacitor 112 may bedisposed inside the non-contact IC 132. The first loop coil 111 and thefirst capacitor 112 respectively connected to this non-contact IC 132are referred to as a non-contact IC unit.

A radio reader/writer 200 has a resonant circuit 210, a main controlunit 231 and the like. The resonant circuit 210 has a loop antenna forcommunication 211 and a capacitor 212. The main control unit 231 has aCPU, a memory, a logic circuit and the like. Furthermore, the radioreader/writer 200 also has a radio conversion unit having a modulationcircuit and a demodulation circuit. The reader/writer 200 is connectedto a host device such as an automatic ticket gate installed at theticket gate in the railroad station for example.

With the system composed of the foregoing radio communication terminal100 and the radio reader/writer 200, data transmission and receipt byradio can be established between the radio communication terminal 100and the radio reader/writer 200.

By using the above-mentioned system, in the case of radio communicationbetween the non-contact IC 132 mounted on the radio communicationterminal 100 and the radio reader/writer 200, the host device transmitsa command to the radio reader/writer 200, the radio reader/writer 200which has received the command from the host device converts the commandinto one for the non-contact IC 132 by means of the radio conversionunit to transmit it to the non-contact IC unit via the loop antenna 210.

The non-contact IC unit replies a response to the radio reader/writer200 in response to the command received therefrom. The radioreader/writer 200 which has received the response from the non-contactIC unit converts the response from the non-contact IC unit to transmitit to the host device.

By the way, as shown in FIG. 1, if the first loop coil 111 composed ofthe non-contact IC unit is disposed in a magnetic field A radiated fromthe loop coil 211 of the radio reader/writer 200, the magnetic fieldradiated from the loop coil 211 of the reader/writer 200 passes throughthe first loop coil 111 composed of the non-contact IC unit. At thistime, the non-contact IC unit receives the magnetic field which haspassed though the first loop coil 111 to obtain induced power necessaryfor communication.

The amount of the power supplied to the non-contact IC unit varies inaccordance with the intensity of the magnetic field received by thefirst loop coil 111 and the stronger the magnetic field intensitybecomes the larger induced power can be obtained. In general, the closerthe non-contact unit approaches the loop coil 211 of the radioreader/writer 200, the larger the induced power obtained from the firstloop coil 111 becomes and as far as getting away from the loop coil 211,the induced power is apt to become small.

If the intensity of the magnetic field radiated from the loop coil 211of the radio reader/writer 200 is constant, the larger electro motiveforce generated from the first loop coil 111 composed of the non-contactIC unit can make stable communication even if the communication distanceis further long. That is, to secure stable communication performance ina long communication distance it is necessary that the induced power islarge also for the communication made at the first loop coil 111composed of the non-contact IC unit.

In the radio IC card, there is no shielding member to shield themagnetic field passing through the loop coil mounted on the radio ICcard. In contrast, in the radio communication terminal 100, for example,a plurality of electronic components and batteries to achieve a phonefunction are incorporated therein, these electronic components andbatteries are shielded so as to prevent electromagnetic interference.Otherwise stated, in the case of the radio communication terminal 100, ashielding member to shield the magnetic field passing through the firstloop coil 111 is mounted thereon. Therefore, a metal object and a metalplate exist close to or back face of the first loop coil 111 composed ofthe non-contact IC unit mounted on the radio communication terminal 100,a wide magnetic field in a free space is not formed as an IC card andcommunication sensitivity is deteriorated as a result.

That is to say, since the presence of a metal just below an antennaconverts the magnetic field which has passed through the antenna into aneddy current on the face of the metal, the magnetic field intensity isweakened, then, only small induced power can be generated as a result.

Therefore, in the present invention, the second loop coil 121 and thesecond capacitor 122 composes the second resonant circuit 120 to disposeit nearby the first loop coil 111 composing the non-contact IC unit,then, the radio communication terminal 100 can increase the inducedpower obtained from the first loop coil 111 composed of the non-contactIC unit. By approximating or matching the center of the first loop coil111 to the center of the second loop coil 121, the radio communicationterminal 100 can further increase the induced power generated from thefirst loop coil 111.

The shape of the second loop coil 121 is may be rectangular or circlefor example and may be any shape. Opposed ends of the second loop coil121 are connected to the second capacitor 122 to configure the resonantcircuit. The number of windings of the second loop coil 121 and thecapacity of the second capacitor 122 are set in advance to valuesmatched to resonate with a frequency drifted from a radio communicationfrequency in consideration of influence of the radio communicationfrequency used in the system and of the surrounding metal object, etc.

As a result, when the radio communication terminal 100 is placed in thespecified magnetic field, the first loop coil 111 composing thenon-contact IC unit mounted nearby the second loop coil 121 and thesecond capacitor 122 induces the power most efficiently by re-radiatingthe magnetic field caused by the number of windings of the second loopcoil 121 and the capacity of the second capacitor 122 (generation ofelectromagnetic field B).

That is, when holding up one face (for example rear face) of the housingof the radio communication terminal 100 into the electro magnetic fieldA radiated from the loop coil 211 of the radio reader/writer 200, thesecond resonant circuit 120 composed of the second loop coil 121 and thesecond capacitor 122 mounted on the one face side resonates with themagnetic field to re-radiate the received magnetic field (generation ofelectromagnetic field B). With this re-radiation, a snake path strongerthan the case of no presence of the second resonant circuit is generatedonto the metal plate of which the rear is in the state of the presenceof the magnetic field generated around the second resonant circuit 120.

This strengthened snake path of the magnetic field increases the powerinduced at the first loop coil 111 composed of the con-contact IC unitmounted on the rear side of the metal plate and the radio communicationterminal 100 can obtain the power roughly the same power as that whenthe other face (for example front face) of the housing of the radiocommunication terminal 100 is held up. As a result, a sufficientcommunication distance can be secured even when one face (for examplerear face) of the housing with the first loop coil 111 composed of thenon-contact IC unit incorporated in the radio communication terminal 100mounted thereon is held up toward the loop coil 211 of the radioreader/writer 200.

As mentioned above, with mounting the first resonant circuit 110composed of the first loop coil 111 and the capacitor 112 and the secondresonant circuit 120 composed of the second loop coil 121 and thecapacitor 122 onto the metal back face, when the rear side of the faceof the first loop coil 111 connected to the non-contact IC 132 is heldup in the electromagnetic field A radiated from the radio reader/writer200, the second resonant circuit 120 composed of the second loop coil121 and the second capacitor 122 resonates. Then, the second loop coil121 generates a magnetic flux and brings it into a snake path toward themetal back face, and as a result, the radio communication terminal 100amplifies the power generated from the first loop coil 111 and enablesmaking the communication distance long.

Thereby, in the communication between the radio communication terminal100 and the radio reader/writer 200, the radio communication terminal100 can secure the stable communication by holding up the loop coilmounted thereon without regard to the front or rear of the loop coilface.

Hereinafter, the configuration examples 1-8 of the radio communicationterminal 100 will be described.

FIGS. 2A and 2B are the views showing the configuration example 1 of theradio communication terminal. FIGS. 3A and 3B are the views showing theconfiguration example 2 of the radio communication terminal. FIGS. 4Aand 4B are the views showing the configuration example 3 of the radiocommunication terminal.

As shown in FIGS. 2A, 2B, 3A, 3B, 4A and 4B, the radio communicationterminal 100 has the first resonant circuit 110, the second resonantcircuit 120, the main control unit 131, the non-contact IC 132, theconnecting line 133, a reception port 141, a transmission port 142, aliquid display 143, an operation button section 144, a buttery 145, andthe like. As described above, the first resonant circuit 110 is composedof the first loop coil 111 and the first capacitor 112 forcommunication. One second resonant circuit 120 is composed of the secondloop coil 121 and the second capacitor 122 for communication. The maincontrol unit 131 and the battery 145 are shielded with the shieldingmember to prevent electromagnetic interference.

As shown in FIGS. 2A, 2B, 3A, 3B, 4A and 4B, the loop area formed by thesecond loop coil 121 is larger than that formed by the first loop coil111. The second loop coil 121 is arranged at an outer circumference ofthe loop formed by the first loop coil 111. The second loop coil 121 isarranged so that the whole thereof is not hidden in a shadow of theshielding member. That is, at lest a part of the second loop coil 121 isprojected from the shade of the shielding member. It is furtherpreferable for the loop area formed by the second loop coil 121 islarger than the area of the shielding member. Thereby, even if the firstresonant circuit 110 is disposed on one side of the shielding member ofthe main control unit 131, the power generated from the first loop coil111 can be amplified by a resonant effect of the second resonant circuit120. Accordingly, the holding up of any face of the radio communicationterminal 100 toward the radio reader/writer 200 can establish the stablecommunication.

Furthermore, as shown in FIGS. 4A and 4B, with arrangement of the secondloop coil 121 along with the outer circumference of the housing of theradio communication terminal 100, it can obtain a further effectiveresonant effect.

FIG. 5 is the view showing the configuration example 4 of the ratiocommunication terminal. FIG. 6 is the view showing the configurationexample 5 of the ratio communication terminal. FIG. 7 is the viewshowing the configuration example 6 of the ratio communication terminal.FIG. 8 is the view showing configuration example of the second resonantcircuit 120 applicable to the configuration examples 4, 5 and 6 of theseradio communication terminals.

As shown in FIGS. 5, 6 and 7, each of the radio communication terminal100 has the first resonant circuit 110, the second resonant circuit 120,the main control unit 131, the con-contact IC 132, connecting line 133,the reception port 141, the transmission port 142, the liquid crystaldisplay 143, the battery 145, a hinge 151 (movable section), a connector152, a unit 161, a unit 162 and the like, respectively. As mentionedabove, the first resonant circuit 110 is composed of the first loop coil111 and the first capacitor 112 for communication. One second resonantcircuit 120 is composed of the second loop coil 121 and the secondcapacitor 122 for communication. The main unit 131 and the battery 145are shielded for preventing the electromagnetic interference.

The housing of the radio communication terminal 100 is composed of thefirst unit 161 and the second unit 162 connected with each other throughthe hinge 151. For example, the housing of the radio communicationterminal 100 is configured to enable folding the first unit 161 and thesecond unit 162 using the hinge 151 as the base point. Or, the housingof the radio communication terminal 100 is configured to make the firstunit 161 be freely rotatable (slidable) to the second unit 162. Theconnector 152 connects the electronic device (for example, main controlunit 131) of the first unit 161 to the electronic device (for example,liquid crystal display 143).

As shown in FIGS. 5, 6 and 7, the loop area formed by the second loopcoil 121 is larger than that formed by the first loop coil 111. Thesecond loop coil 121 is arranged at an outer circumference of the loopformed by the first loop coil 111. The second loop coil 121 is arrangedso that the whole thereof is not hidden in the shadow of the shieldingmember. That is, at lest a part of the second loop coil 121 is projectedfrom the shade of the shielding member. It is further preferable for theloop area formed by the second loop coil 121 is larger than the area ofthe shielding member.

As shown in FIG. 5, even if the first resonant circuit 110 is disposedon one side with an interposition of the shielding member of the maincontrol unit 131 in the second unit 162, and even if the second resonantcircuit 120 is disposed on the other side with an interposition of theshielding member of the main control unit 131 in the second unit 162,the power generated from the first loop coil 111 can be amplified by aresonant effect of the second resonant circuit 120. Accordingly, theholding up of any face of the radio communication terminal 100 in eitherstate in which the radio communication terminal 100 is folded or foldedwith a slide rotation toward the radio reader/writer 200 can achieve thestable communication.

And as shown in FIG. 6, even if the first resonant circuit 110 isdisposed on one side with the interposition of the shielding member ofthe main control unit 131 of the second unit 162, and even if the secondresonant circuit 120 is disposed on the same side, the power generatedfrom the first loop coil 111 can be amplified by the resonant effect ofthe second resonant circuit 120. Accordingly, the holding up of any faceof the radio communication terminal 100 in either state in which theradio communication terminal 100 is folded or folded with the sliderotation toward the radio reader/writer 200 can achieve the stablecommunication.

And as shown in FIG. 7, even if the first resonant circuit 110 isdisposed on one side with an interposition of the shielding member ofthe main control unit 131 of the second unit 162, and even if the secondresonant circuit 120 is disposed on the other side with theinterposition of the shielding member of the liquid crystal display inthe first unit 161, the power generated from the first loop coil 111 canbe amplified by the resonant effect of the second resonant circuit 120.Accordingly, the holding up of any face of the radio communicationterminal 100 in either state in which the radio communication terminal100 is folded or folded with the slide rotation toward the radioreader/writer 200 can achieve the stable communication.

As shown in FIG. 8, the second loop coil 121 has a switch 123 to openand close the loop with linkage (synchronization) with a movement of thehinge 151. Thereby, in the state of folding the radio communicationterminal 100 or folding it with the slide rotation, the second loop coil121 can exert the resonant effect of the second resonant circuit 120.

FIG. 9 is the view showing the one example of the radio communicationterminal housing case for housing the radio communication terminal. Asshown in FIG. 9, the case 300 houses, for example, the radiocommunication terminals 100 (but, it may not provided with secondresonant circuit 120) shown in FIGS. 5, 6 and 7. Each case 300 may bestructured so as to enable housing the radio communication terminal 100(but, may not provided with second resonant circuit 120) shown in FIGS.2A, 2B, 3A, 3B, 4A and 4B, respectively. The case 300 has a secondresonant circuit 320 composed of a second loop coil 321 resonating bythe magnetic field from the radio reader/writer 200 of a communicationpartner of the radio communication terminal 100 together with the firstloop coil 111 mounted thereon.

That is, when each case 300 houses the radio communication terminal 100(but, may not provided with second resonant circuit 120) shown in FIGS.5, 6 and 7, respectively, to hold up the case 300 toward the radioreader/writer 200, the radio communication terminal 100 can amplify thepower generated from the first loop coil 111 thereof by the resonanteffect from the second resonant circuit 320 in the case 300.Accordingly, the holding up of either face of the case 300 with theradio communication terminal 100 housed therein toward the radioreader/writer 200 can cause the stable communication.

Like this, the use of the case 300 can increase the loop area of thesecond loop coil 321 to exert further dramatic effect resulted from theresonant effect.

FIG. 10 is the view showing one example of the radio communicationterminal sheet capable of being mounted (stuck) to the radiocommunication terminal. As shown in FIG. 10, a radio communicationterminal sheet 400 can be mounted to, for example, the radiocommunication terminals 100 (but, may not provided with second resonantcircuit 120) shown in FIGS. 5, 6 and 7. The sheet 400 may be structuredso as to be usable by being mounted to the radio communication terminals100 (but, may not provided with second resonant circuit 120) shown inFIGS. 2A, 2B, 3A, 3B, 4A and 4B. This sheet 400 has a second resonantcircuit 420 composed of a second loop coil 421 and a second capacitor422 resonating together with the first loop coil 111 mounted on theradio communication terminal 100 by the magnetic field from the radioreader/writer 200 of the communication partner of the radiocommunication terminal 100. This loop coil 421 may be formed byprinting, wiring or etching. The second capacitor 422 may be an actualcomponent and also one made by pattern printing. The central section ofthe sheet 400, in other words, an inside section of the second loop coil421 may be a hollow. And the sheet 400 is made of a material not toshield the electromagnetic field.

Otherwise stated, by mounting the sheet 400 to one face of the radiocommunication terminal 100 (but, may not provided with second resonantcircuit 120) in the sate of folding or folding with a slide rotationthereof, the radio communication terminal 100 can amplify the powergenerated form the first loop coil 111 thereof by the resonant effect ofthe second resonant circuit 420 of the sheet 400. Accordingly, theholding up of any face of the radio communication terminal 100 with thesheet 400 mounted thereto toward the radio reader/writer 200 can achievethe stable communication.

As described above, by utilizing the sheet 400, the radio communicationterminal 100 can increase the loop area of the second loop coil 421 toobtain the great effect resulted from the resonant effect.

FIG. 11 is the view showing one example of the radio communicationterminal display device capable of being mounted (stuck) to the radiocommunication terminal. As shown in FIG. 11, a display device 500 can bemounted to, for example, the radio communication terminal 100 (but, maynot provided with second resonant circuit 120) shown in FIGS. 2A, 2B,3A, 3B, 4A, 4B, 5, 6 and 7. The display device 500 has a second resonantcircuit 520 composed of a second loop coil 521 resonating together withthe first loop coil 111 mounted on the radio communication terminal 100by the magnetic field from the radio reader/writer 200 of thecommunication partner of the radio communication terminal 100.Furthermore, the second loop coil 521 is provided with display meanssuch as a light emitting diode. This loop coil 521 maybe formed byprinting, wiring or etching. The central section of the display device500, in other words, the inside section of the second loop coil 521 maybe a hollow. The display device 500 is made of a material not shieldingthe electromagnetic field.

That is to say, when mounting the display device 500 to the radiocommunication terminal 100 (but, may not provided with second resonantcircuit 120) to hold up the radio communication terminal 100 with thedisplay device 500 attached thereto toward the radio reader/writer 200,the radio communication terminal 100 can amplify the power generatedform the first loop coil 111 thereof by the resonant effect of thesecond resonant circuit 520 of the display device 500. Accordingly, theholding up of any face of the radio communication terminal 100 with thedisplay device 500 mounted thereto toward the radio reader/writer 200can achieve the stable communication. As described above, by utilizingthe display device 500, the radio communication terminal 100 canincrease the loop area of the second loop coil 521 to obtain the greateffect resulted from the resonant effect. Moreover, a light emittingdiode 522 provided with the second loop coil 521 of the display device500 emits light by receiving the magnetic field from the radioreader/writer 200. Thereby, the display sheet 500 can guide thecommunication status. For example, in response to the light emittingstate of the diode 522, the radio communication terminal 100 canmaintain further excellent communication state by approximating it tothe radio reader/writer 200.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A radio communication terminal provided with an electronic deviceshielded to prevent electromagnetic interference, in a housing,comprising: an integrated circuit; a first resonant circuit connected tothe integrated circuit to make non-contact communication with anexternal device; and a second resonant circuit resonating with the firstresonant circuit.
 2. The radio communication terminal according to claim1, wherein a loop area formed by a loop coil of the second resonantcircuit is larger than that formed by the first loop coil.
 3. The radiocommunication terminal according to claim 1, wherein the loop coil ofthe second resonant circuit is arranged at an outer circumference of aloop formed by the loop coil of the first resonant circuit.
 4. The radiocommunication terminal according to claim 1, wherein the loop coil ofthe second resonant circuit is arranged along with an outercircumference of the housing.
 5. The radio communication terminalaccording to claim 1 wherein the loop coil of the first resonant circuitis arranged on one side of the radio communication terminal withinterposition of a shield member shielding the electronic device, andthe loop coil of the second resonant circuit is arranged on the otherside of the radio communication terminal.
 6. The radio communicationterminal according to claim 1, wherein the housing is composed of twounits connected with each other through a movable section, and the loopcoils of the first and the second resonant circuits are arranged at oneunit among the two units.
 7. The radio communication terminal accordingto claim 1, wherein the housing is composed of two units connected witheach other through a movable section, the loop coil of the firstresonant circuit is arranged at one unit among the two units, and theloop coil of the second resonant circuit is arranged at the other unitamong the two units.
 8. The radio communication terminal according toclaim 7, wherein the second resonant circuit has a switch for openingand closing the second resonant circuit by linking with a movement ofthe movable section.
 9. A radio communication terminal housing case tohouse a radio communication terminal provided with a first resonantcircuit connected to an integrated circuit to make non-contactcommunication with an external device, comprising: a second resonantcircuit resonating with the first resonant circuit.
 10. A radiocommunication terminal sheet can be mounted to a radio communicationterminal provided with a first resonant circuit connected to anintegrated circuit to make non-contact communication with an externaldevice, comprising: a second resonant circuit resonating with the firstresonant circuit.
 11. A radio communication terminal display device canbe mounted to a radio communication terminal provided with a firstresonant circuit connected to an integrated circuit to make non-contactcommunication with an external device, comprising: a second resonantcircuit resonating with the first resonant circuit; and light emittingmeans emitting light by a current induced by the second resonantcircuit.
 12. The radio communication terminal according to claim 1,wherein a loop coil of the second resonant circuit is arranged so that acenter of the loop coil of the second resonant circuit gets closer to acenter of a loop coil of the first resonant circuit.
 13. The radiocommunication terminal according to claim 1, wherein a loop coil of thesecond resonant circuit is arranged so that a loop area formed by thesecond resonant circuit is larger than that of a shielding memberincorporated in the radio communication terminal.